Agricultural farming is a vital component of the food supply system in any country. In the past, such farming was extremely labour intensive. However, over the years technology has been applied to automate various tasks and thus improve the efficiency of the farming as a whole.
One area where machines have been particularly useful is in repetitive functions such as planting. In order for an individual plant (or crop) to enjoy optimum growing conditions, certain conditions must be met; one such condition is inter-plant spacing. Machines can be designed to provide constant spacing.
Although automation of many farming functions has taken place, there are still aspects where a human interaction is preferable (e.g. where the plant may be damaged). In a semi-automated system, the most likely point of a ‘bottle neck’ is with the human component.
Other disadvantages of involving humans include labour charges and limited work hours. With a machine, a minimal human workforce can successfully carry out the same work of much larger all-human workforce.
Certain plants, for example lettuces, leeks, the tobacco plant, and the Brassica plant (examples of which are cabbages and cauliflowers), are grown in propagation trays until they are a reasonable size. Once the plants are of a suitable size, they can be transferred into a field so that they grow to maturity. Each propagation tray comprises a grid of cells, with each cell housing an individual plant.
Traditionally the transfer of such plants to a field has involved the manual removal of each plant from the tray, and then feeding the plants into a planting machine. The need for human input means that this planting system suffers from the aforementioned problems. There is a need for a machine that is capable of carrying out the human elements of the planting process without damaging the crops being planted.
Ride-on, tractor-drawn planters are known, in which one or more people on the trailed unit manually remove plants from the propagation trays and then place the plants into a moving array of cups. The cups transport the plants to a chute, and they are dropped into the chute which then conveys the plants down to the ground. The speed at which the array of cups is moved thus, in part, determines the eventual spacing of the plants in the ground. However, in addition to requiring a large amount of labour, the use of drop chutes presents a further problem. The time taken for a plant to fall through the chutes will depend on a number of factors, including the weight of the root portion of the plant (which is very dependent on the moisture content) and the quantity and configuration of the foliage. These factors can vary from tray to tray, and indeed from cell to cell within a single tray, and so even if extracted plants are presented at a uniform rate to the top of the drop chute, the rate at which they emerge will vary and so leads to a variation in plant spacing.
Automated planters are known in which rows of plants are pushed out at a time by an array of pusher members (e.g. rods) from “below” the propagation tray (i.e. from the reverse side, the side opposite to that of the foliage). The pushed-out plants are conveyed by suitable means to drop chutes, through which they are conveyed to arrive at a planting shoe. From the shoe the plants are deposited in the ground. Again, the use of drop chute causes difficulties when trying to achieve even plant spacing. Also, blockages can occur. Subsequent handling of the plants, after they have been pushed out of the tray, poses yet further problems. Additionally, pushing the plants out from the trays can damage their roots, and variations in root-ball density and consistency can lead to different plants being pushed out to different extents. This can further complicate subsequent handling.
There is, therefore, a need for an automated planter that overcomes, at least partially, one or more of the problems associated with the prior art.